What is this in my rock?

[Freddie L]

Hi, last night I noticed something in my live rock Id never seen before.It only comes out at night with the moon lights and it has long thin tenacles(7 or more) kind of beigh and seems to reach out feeling for stuff yet never comes out of its hole? Any Idea, sorry no pics...

 

[Fluff]

Sounds like a spaghetti worm. They send out sticky tenticles to pic up food particles.